Hong Gil-Dong (Lee Je-Hoon) runs an illegal detective agency with President Hwang (Go Ara). They try to take down evil people following the will of President Hwang’s late father. Hong Gil-Dong is able to track virtually anyone down in an hour or less, except for Kim Byeong-Duk (Park Geun-Hyung) who has eluded him for many years. Kim Byeong-Duk is the man who killed Hong Gil-Dong’s mother. Hong Gil-Dong’s memory begins at the age of 8 when he was mother was killed.
Finally, Hong Gil-Dong learns of Kim Byeong-Duk’s location and drives there late at night. Right before he arrives, Kim Byeong-Duk is kidnapped and only his granddaughters Dong-Yi (Roh Jeong-Eui) and Mal-Soon (Kim Ha-Na) are left. Following his urge for revenge, Hong Gil-Dong takes the granddaughters to find their grandfather. Soon, Hong Gil-Dong finds himself up against the ultra dark and powerful Gwangeunhwe organization.